微生物壳聚糖酶的研究及其降解产物壳寡糖在食品领域的应用

介绍了壳聚糖酶的来源、分类及其理化性质,总结了国内外产壳聚糖酶菌株的研究进展,并对其降解产物壳寡糖的生理功能和在食品领域中的应用进行了概述。     

有效微生物菌群(EM)对蟹鲈混养模式下养殖水体菌群结构的影响

为探究定期添加有效微生物菌群(EM)对蟹鲈混养养殖水质和菌群结构的影响,实验对混养水体进行了Ⅰ期(4月10号)、Ⅱ期(4月20号)、Ⅲ期(4月30号)和Ⅳ期(5月10号)的监测,并通过水质理化指标、16S rRNA基因高通量测序技术分析了每个时期的水质和菌群结构.高通量测序结果显示,实验期间水体主要优势菌门为变形菌门、...     

瘤胃微生物总DNA快速提取法研究

本文介绍了一种简便快速地提取瘤胃微生物细胞总DNA的方法,该法是对提取植物的CTAB法进行改进而成。与经典反复冻融 SDS/蛋白酶K裂解法相比,该法可在数小时内高效地提取瘤胃内容物总DNA,经琼脂糖凝胶电泳对所提取瘤胃微生物总DNA进行检测,证明所获得的瘤胃总DNA符合分子生物学操作要求。     

Application of 16S rDNA Sequence Analysis Technique in Microbial Detection

16srDNA既具有保守性区域。又具有高变性区域,是生物的种属鉴定和系统进化关系的重要分子基础。以16srDNA为目的物的现代分子生物学技术能精确地揭示微生物种类和遗传的多样性,从而16srDNA序列分析成了微生物分类鉴定主要依据。该方法克服了传统微生物培养方法的限制,操作方便、检测快速准确且灵敏度高,已被广泛应用到菌种鉴定、群落对比分析、群落中系统发育及种群多样性的评估等领域,是一种客观和可信度较高的分类方法。     

Tundra plants protect the soil surface from UV

In the Arctic, seasonal ozone depletion is resulting in periods of enhanced UV-B radiation at ground level while regional climate change is associated with increasing temperatures. These changes are likely to alter plant distribution, biodiversity and morphology, which may have knock-on effects for microbially driven biogeochemical cycling and other soil processes. Our study examined the transmission of solar UV radiation through arctic tundra plants using a portable UV radiometer and the DLR-biofilm biological UV dosimeter. A strong negative correlation was found between vegetation cover and UV transmission to the soil surface. Penetration of UV to the soil beneath tundra plants varied depending upon plant morphology, being greater through low creeping plants than cushion plants, grasses or mosses. UV transmission to the soil surface beyond the foliage edge also varied with plant morphology and the presence of flowers.     

瘤胃微生物的传统定量方法在反刍动物中的应用

瘤胃微生物作为一个完整的生态系统,受日粮成分、饲养方式、季节等诸多因素的影响,认识瘤胃微生物的功能及其活动规律复杂而困难。瘤胃微生物的传统定量方法有亨氏滚管法和最大或然数计数法,二者有着各自的优缺点。本文综述了瘤胃微生物的传统定量方法的应用状况及各自的优缺点。     

Inoculation of root microorganisms for sustainable wheat-rice and wheat-black gram rotations in India

The scarcity of non-renewable resources such as soils and fertilizers and the consequences of climate change can dramatically influence the food security of future generations. Mutualistic root microorganisms such as plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) can improve plant fitness. We tested the growth response of wheat (Triticum aestivum [L.]), rice (Oriza sativa [L.]) and black gram (Vigna mungo [L.], Hepper) to an inoculation of AMF and PGPR alone or in combination over two years at seven locations in a region extending from the Himalayan foothills to the Indo-Gangetic plain. The AMF applied consisted of a consortium of different strains, the PGPR of two fluorescent Pseudomonas strains (Pseudomonas jessenii, R62; Pseudomonas synxantha, R81), derived from wheat rhizosphere from one test region. We found that dual inoculation of wheat with PGPR and AMF increased grain yield by 41% as compared to un-inoculated controls. Yield responses to the inoculants were highest at locations with previously low yields. AMF or PGPR alone augmented wheat grain yield by 29% and 31%, respectively. The bio-inoculants were effective both at Zero and at farmers’ practice fertilization level (70 kg N ha⁻¹, 11 kg P ha⁻¹ in mineral form to wheat crop). Also raw protein (nitrogen × 5.7) and mineral nutrient concentration of wheat grains (phosphorus, potassium, copper, iron, zinc, manganese) were higher after inoculation (+6% to +53%). Phosphorus use efficiency of wheat grains [kg P grain kg⁻¹ P fertilizer] was increased by 95%. AMF and PGPR application also improved soil quality as indicated by increased soil enzyme activities of alkaline and acid phosphatase, urease and dehydrogenase. Effects on rice and black gram yields were far less pronounced over two cropping seasons, suggesting that AMF and PGPR isolated from the target crop were more efficient. We conclude that mutualistic root microorganisms have a high potential for contributing to food security and for improving nutrition status in southern countries, while safeguarding natural resources such as P stocks.     

阿维菌素对蔬菜地土壤微生物及土壤酶的生态毒理效应

研究了阿维菌素对蔬菜地土壤微生物和土壤酶的生态毒理效应.实验结果表明,阿维菌素在低浓度时（1～10 mg kg^-1）对土壤脲酶活性和脱氢酶活性有轻微的激活作用,而对土壤微生物呼吸强度没有明显的影响;在高浓度时（50～100 mg kg^-1）对土壤微生物呼吸强度、脲酶活性以及脱氢酶活性均有明显抑制作用;不同浓度阿维菌素在不同程度上均会造成土壤微生物生物量的减少和过氧化氢酶活性被强烈激活.     

Effects of antibiotics on soil microorganisms: time and nutrients influence pollution-induced community tolerance

A method for the detection of the effects of antibiotics on soil microbial communities was optimised in the present study. We investigated the influence of measurement time and nutrient status on the pollution-induced community tolerance (PICT), using the sulfonamide sulfachloropyridazine (SCP) as model compound. The tolerance development in soil microcosms that were exposed to SCP under different conditions was compared with the background tolerance in SCP-unexposed microcosms. The tolerance of bacterial extracts from the soil microcosms was determined in Biolog^® multiwell plates as the SCP sensitivity of a range of physiological processes. The background tolerance was not affected by soil nutrient amendments, but an influence of the inoculum density in the microtiter plates was observed. Still, the variance of the background tolerance was low, which is in favour of the usage of community tolerance measurements for a selective detection of a toxicant impact. In line with the assumptions of the PICT concept, soil amendment with SCP led to an increase in community tolerance. This tolerance development was enhanced upon additional soil amendment with fresh pig slurry, and less by alfalfa meal addition. Tolerance increases were observed after a soil exposure to SCP of only 7 days, possibly because nutrient input facilitates the fast adaptation of the soil microbial community. However, a further increase in exposure time led to variable changes in the observed tolerance. Prolonged tolerance detection in the microtiter plates (11 days) enabled a clearer differentiation between different soil treatments, as it better resolved the EC₅₀ values of processes with a high tolerance to bacteriostatic antimicrobial compounds. For the detection of antibiotic effects on soil microbial communities, it is therefore recommended to use nutrient amendments (possibly fresh pig slurry), to standardize the soil exposure time, and to extend the period of Biolog plate measurement beyond 7 days.     

养猪生产中"肺肠同制"理论与替抗实践

在“禁抗”的大背景下,人们必须改变与病原微生物打交道的策略,从以往通过抗生素的“打打杀杀”到“和谐共处”。文章根据中医传统“肺与大肠相表里”理论,探索替抗的“肺肠同制”技术路径,并阐明只有替抗产品与替抗管理同时进行,才能够真正实现使用“替抗”方法与抗生素使用时达到同样、乃至更好的效果。